Gas turbine cooling system



GAS TURBINE COOLING SYSTEM Filed June so, 195o 's sheets-sheet 1 INVENTOR. WILTDN E1. LIJNDEIUIET.

.BYZJL A.

ATTEIRNEY w. G. I UNDQUlsT 2,672,013

3 Sheets-Sheet 4 INVENTOR.

WQTDN E. LUNDQUEIT.

- ATTDRNEY Mrch 16, 1954 June 30, 195o w. G. I UNDQUIST GAS TURBINE COOLING SYSTEM March 16, 1954 3 Sheets-Sheei 5 Filed June 50, 1950 INVENTOR. WILTIIIN E LUNDQLIIS'IZ 8% A ATTEIRNEY ing said air compressor.

Patented Mar. 16, 1954 "f Wilton G. vLundoluist, Hoholfrus,v -N J.,

assignor; to

Delaware [Application Junej30, 1950, Serial No.`171,349 6. Claims. (C1. (iO-339.66)

AThis -invention relates to '-gas turbine cooling systems and Iis'parti-cularly directedto an arrangement for providing a Agas'turbine-power plant with ,cooling air.

'The efciency and performance of a gas turbine power-plant increases withv increase in the temperature ofthe gas turbine Working-fluid. Accordingly,- it is desirable to provide means for cooling the turbine to permit gas turbineoperation at-high gastemperatures. vAn objectv ofthe present -invention -comprises the provision of -a novel and eflicient arrangement for supplying and -distributing cooling airover portions of'a gas Yturbine powerplant.

VIn accordance with the presentuinvention an airimpeller, drivably connected to they turbine rotor, supplies the turbine with Icooling air. lA portion of the air supplied bysaid impeller is used for cooling various accessoryunits of the gas turbine power plant and' foncooling' the turbine stator structure. Another portion of the air supplied; by said impeller is received byk a second impeller which causes said air to ow in heat exchange relation with `the periphery of theyturbine rotor.

Othery objects of the invention will become apparent upon reading the annexed Idetailed description in connection with "the drawing in which:

1 Figure 1 Yis a schematic sectional view of a p ortion 'of agas turbinevDOpWer plant embodyingthe invention;

ure 1; and

jEigure is a view illustrating a Vdriving connection to one of the auxiliaryunits.

AA conventional gas turbine power kplantpcomprises anair compressor which suppliesnairjfor combustion to a combustion chamber. From said combustion chamberv the working fluid comprising combustiongasesand excess air,vis directed againsttheblades ofthe turbine rotor for 'driving said rotor, said rotor in turn ldriv- The Working lfluid-discharges rearwardly from'the turbine rotor to providethe .power plant with* forward propulsiye thrust. AconveA tionalbladed propeller may also be'driven by the turbine rotor. Y'fluch a power plant is illustratedin applicants prior latent No. 2,469,439.

Referring ,to the jdrawing, aportionof la gas turbine power plant I0 isillustrated as compris- 'ing a two-stage rotorv I2, said rotor consisting of 3' a first-stage rotor disc Eiland a second stage`v rotor disc I6. A plurality Vof circumferentially spaced blades I8 are secured to .and about the periphery of the rst stage rotor disc I4 and aplura'lityv of Y circumferentially spaced blades :26 .are secured tol and-about the periphery -of the second stage rotorV disc` I6. A plurality of vstator blades 22 are `disposed.- between said rst and second stage rotor blades I8 and 20.

The turbine rotor fdisc I4 has an annular flange 24abutting a corresponding annular flange- 26 on the rotor disc fI6, -said vrotor -discs being clamped together byl a` plurality of circumferentially -spaced bolts A28-extending through said anges. The flange 24'has aplurality vof Aradially extending splines or teeth 25 meshing with corresponding splines-ZI-.on the flange 26 -Whereby said splinesv maintain the rotor discsfl4 and I6 coaxial. Said splines 25 and 21 may be disposed around the entire circumference of said flanges or. as illustrated, only inthe regions adjacent to and on each side ofthe bolts 28. l-The rotor .discs are alsoelamped together at their hub portions by a nut 36: threaded cna hollow shaft32extend-ing throughsaid hub portions. A spacer ring 34 `is disposed between the hub Yportions of vthe rotor-discs I4`A and I6kand-airst Washer 36wis disposedbetween the hub portion of the rotor disc. I4 and the nut 36 anda secondwasher is disposedbetween the rotor disc I6- and a shoulder.- 40 -on the shaftlwwhereby said Vnut iseffectiveto vclarnp the rotor assembly againstthe shaft shoulder 46. `The washer-36 is provided with aplurality` of radially extendingI splines or teeth-35 meshing `with corresponding splines-31 on the rotor disc I4whereby said splines center the turbine rotor-discs relative to the axis of the shaftA 32.

`AThe shaft 32 has-a conical flange 42 which is drivably connected by theA bolts 28 to one sidev of the turbine rotor I2 adjacent tothe periphery of said rotor. A- second shaft 44 has a conical end-which is drivably connected bythe bolts 'v 281` to the other side ,of the turbine rotor adjacent to theperiphery ofusaid rotor. llfor thisr latterpurpose the turbine rotor disc I4 is providedy with a plurality of circumferentially spaced bosses 46, the bolts 28 Yextending through said bosses andftlirough an annular-jange on the shaft 44. The shaft V4t! is drivablyA connected to an air compressorv (not shown) which supplies air under pressure tothe combustion chamber ofthe power plant I0. f From the combustion chamber" 50 the combustion gases land excess air are jdirected againstj'the'rst stage rotorblades I8 by stator blades 52. From the iirst stage rotor blades I8, said gases are directed against the second stage rotor blades by stator blades 22. The gases discharge from the rotor blades 2c into an annular exhaust duct 54 and thence discharge rearwardly into the surrounding atmosphere to provide the power plant with forward propulsive thrust.

A plurality of power plant auxiliary units, schematically indicated at 56, are disposed about the shaft 32 in the annular space between said shaft and the exhaust duct 54. The units 56 may comprise fuel and/ or oil pumps and are drivably connected to the shaft 32 bymeans schematically indicated at 58. The means schematically indicated at 58 may also provide a lbearing for the shaft 32. A suitable driving connectionV 58 lfor one of the units is illustrated in Figure l0 in which a gear 58a, securedto the shaft 32, is disposedfin meshing engagement; with 4a pinion A58o drivably connected to said unit 56. Each of the other units v56 may be similarly connected to the shaft 32.- Y

f The shaft 32 isjournaled in a bearing structure 60.@ The bearing structure 60 comprises two annularfbearing members l62 and 64 bolted together and between which annular bearing diaphragme 66 and 68 are secured. The bearing diaphragme 6,6and- 68 are-each connected to the radially inner endsof a plurality of circumferentially spaced hollow struts 10 extending through the annular exhaustduct 54. The radially outer ends of the hollow struts 1||-are=secured to a hollow supporting ring 12disposed aboutthe'exhaust duct 54, said ring being secured to the power plant housing 14 by annular plates 16. I nl addition the auxiliary units 56 are supported in position about the shaft 32-`by the diaphragm 68. With this construction, the turbine rotor, the bearing structure 6I)r and the" auxiliary Aunits' 56' are supported from the power plant housing; 14 byA the hollow struts 1d and the hollow ring 12. The turbine stator blades 22 are 'also supported from the ring 12. Thusthe turbine stator blades 22 are secured to a bracket structure 18 which in turn is secured to a plurality of circumferentiallyspaced and relativelyeshort hollow struts 80 connected to thevring 12.

j A-conventional centrifugal type-air impeller 82 is secured to the rear end of the'shaft 32 bya nut 8,4. said'l l-nutclamping the Vimpeller p82- against a shoulder on` said shaft-` A iixed annular shroud 86 extends-across the outer ends of the blades of the impeller 82a.- AA-forwardextension 88 of said shroud-'86 isAsecured-to the bearing-diaphragm SBvand engages the inner -wall of theannular exhaustduct .54 rearwardly of the hollow struts 10. An annular diaphragm 90 engages the inner wall of the exhaust duct 54 forwardly of the hollow struts 10, the" radially inner end of said diaphragm being secured to the bearing member 62. 'With this arrangement the shroud 86, its forward extensionf88 and the diaphragm 60 form an annular chamber 92 about the rear end of the shaft 32 and within which the auxiliary units 56 are disposed andinto which the hollowstruts 1I) extend. g i

The radially inner ends ofthe struts-'10 are open to the chamber92 and thel radially outer ends of.. said struts are in communication with the interior vof the hollowfring 12 through holes 94. The interior of the hollow ring 12 is in communicationwith theshort hollow struts 88 and said strutsareprovided with holes 36. The struts 18, ring 12 andstruts. 8Il4 thereby. provide communication between thechamber 92 and the annular chamber 98 within the power plant housing 14 and disposed about the exhaust duct 54 and the turbine stator structure 18.

A sleeve |00 surrounds that portion of each strut 1n extending through the exhaust duct 54 to protect said strut from the hot exhaust gases of the turbine. VThe bearing diaphragm'- 68 has holes |02 providing for communication of the chamber 92 with the inner end of the annular space between each sleeve |00 and its associate strut 10. The outer end of each said annular space is in communication with the chamber 98.

During power plant operation, the shaft 32 is driven by the turbine I2 whereupon the centrifugal impeller 82-supplies relatively cool air from the surrounding atmosphere to the chamber 92. From the chamber 32 air flows through the hollow strut 10 and thence through the ring 12, the struts and openings 96 in said struts into the chamber`^ 913 whereupon said airvr ilowsl 'over fthe statorL structure 18 to cool said structure.` From the chamber 98 `this cooling air discharges. into the surrounding atmosphere through holes (not shown) in the housing 14. This cooling of the turbine statorstructure permits better control of theA clearances between the turbine rotor-blades and the cooperating stator structure.

Air also ilows from the chamber 92 to the chamber 93 through the annular space .between .each sleeve I8!! and its associated-strut'10..- This air flow keeps the struts 10-relative1y'cool andfalso helps to cool the stator structure 18. .The :struts lll support the bearing structure 60 -for the rear end of the turbine rotor. The maximum safe allowable load for-each. strut..1|l obviouslyv increases with decrease -in temperature of said struts. Accordingly, it is important. that the struts T be cooled well below the high temperature of the exhaust gases surrounding vsaid struts in the exhaust. duct 54.. Y Y

A portion of.. the air supplied. by the impeller 82 is used for cooling .the periphery. or rim of the turbine rotor.. .For this purpose..the shaft 32 is hollow and holes |04 through said shaft provide communicationbetween the rear end of-said shaft and the chamber S2. The forward end ofthe hollow shaft 32 is provided with holes IIlgcom municating with an annular chamber |08 formed between the shafts 32 and 44. An annularshroud IIGJis secured to vthefturbine. rotor discY I 4 between the shaft fiange'48 and the bosses 46. A second shroud member` I|2. is secured to thefrotor disc I4 to,A forma streamlined annularairentrance opening between theshrouds III! and II2 vto .the annular space between the shroud ||0 .andthe rotor disc I4. A plurality of. circumferentially spaced blades I I4. are disposed across said annular space thereby, forming acentrifug'al impeller rotatable. with andY disposed on the `combustion chamber or high temperature side ofp'vthe rotor disc I4. The blades I4 are secured, as by welding, to the shroud I IIl, shroud I2 and/or to the adjacent side of the'turbine rotor disc I4. The bosses 46 are preferably streamlined and are disposed between the blades II-4 as best seen in Figure 3.

The centrifugal impeller formed by the blades II4 draws air from the .annular chamber |88 and supplies'said air toV the periphery of the turbine rotor. At the turbine rotor periphery said. air ows through passages I 6 between the root ends of the turbine rotor` blades, said air discharging from the passages III; into the exhaust duct 54. 'I he specific turbinerotor and .blade structure formingthe. passagesl I6 constitutes no part ofV the present invention and a vpreferred construc- .5 tioniiis; ful-1y .fedisclosedsin copending application Serial No. 696,287.1iled September l1, 1946 in the name of F. P. Sollinger, now Patent No. 2,603,453-

With-the above described-cooling systemfthe airK supplied by the -imp-e1ler'i82 enters the chamber 192 rand -owsh overthe yauxiliary units 156 -to cool said runits. -A- portion of. the air supplied-.to the chamb er 92- -lows radiallyv outwardly' through the '.hollowstruts-lil -into the chamber 98- to cool the turbine stator structure` 18. Another-portion of the airl supplied to the-chamber 92 flows-between the sleeves |06 and their associated struts 10 to cool said struts and to supply additional statorcooling air to the-chamber 98. The remaining portion --of Athe l`vair vsupplied' to the chamber 92- -by -the limpeller `A`.82 enters the hollow shaft 32 .at the holes |04 and then ows from the other end of said shaft through holes |06 into the chamber |08 within the shaft 44. This latter portion of the air is drawn between the impeller blades I4 and is forced radially outwardly by said blades to the periphery of the turbine rotor. From the periphery of the turbine rotor this latter air flows through the passages IIB between the root ends of the impeller blades thereby cooling the periphery of the turbine rotor. The various flow paths of the cooling air for the turbine are indicated by arrows in Figure 1.

While I have described my invention in detail in its present preferred embodiment, it will be obvious to those skilled in the art, after understanding my invention, that various changes and modifications may be made therein without departing from the spirit or scope thereof. I aim in the appended claims to cover all such modifications.

I claim as my invention:

l. A gas turbine power plant comprising a rotor; a plurality of circumferentially spaced a bosses on said rotor adjacent to its periphery; a shaft secured to said rotor at said bosses; an annular member secured to said rotor between said shaft and bosses, said member extending radially inwardly from said bosses in spaced relation to the adjacent end face of said rotor; and vanes extending between said member and the adjacent rotor end face to form a centrifugal impeller for supplying cooling air to the periphery of said rotor through the spaces between said bosses.

2. A gas turbine power plant comprising a rotor having a plurality of blades; a shaft drivably connected to said rotor; a stator structure surrounding said rotor blades and supporting a plurality of stator blades cooperable with said rotor blades; a combustion chamber for supplying combustion gases to said blades for driving said rotor; an annular duct for receiving the ex# haust gases from said blades, said duct surrounding said shaft; a bearing for said shaft; a plurality of hollow struts for supporting said bearing and shaft, said struts extending through said annular duct; an air impeller drivably connected to said shaft; passage means providing communication between the discharge end of said impeller and the radially inner ends of said hollow struts for flow of cooling air from said impeller into said hollow struts; and passage means providing communication between the radially outer ends of said hollow struts and said stator blade supporting structure for flow of cooling air from said struts over said stator structure.

3. A gas turbine power plant comprising a rotor having a plurality of blades; a shaft drivablynconnectedf tof said-rotor; .a ff stator;v structure surrounding said rotor bladesV ande supportingga plurality sof VAstator :blades r cooperable fwith= said rotor blades a: combustion chamber for. supply.- ing x combustionr gases to said, bladesA for driving said rotor; .-an -annular duct f or receiving. the exhaust gases fromsaid blades;saidiductsurrounding. saidshaft; a; bearing ,for1 said shaft; fafpluralityeof hollowzstruts for supportinggsaid'bearingand shaft'said struts extending, through said annular, duct; v`a jacket, surrounding l at least; that portion of z-each- :ofA said struts-:withinsaidzzduct; van air.in-ipel'ler.drivably connectedxto said shaft; meanslproviding communication between the., discharge end of said impeller and the radiallyinner endsof-.said hollow s trutsand jackets for flow of cooling air from said impeller into said hollow struts and jackets; and passage means providing communication between the radially outer ends of said hollow struts and said stator blade supporting structure for flow of cooling air from said struts over said stator structure.

4. A gas turbine power plant comprising a rotor having a plurality of blades; a shaft drivably connected to said rotor; a stator structure surrounding said rotor blades and supporting a plurality of stator blades cooperable with said rotor blades; a combustion chamber for supplying combustion gases to said blades for driving Vsaid rotor; .an annular duct for receiving the exhaust gases from said blades, said duct surrounding said shaft, a plurality of power plant auxiliary units drivably connected to said shaft .and disposed about said shaft; a plurality of hollow struts extending through said annular duct for supporting said rotor and auxiliary units; an air impeller drivably connected to said shaft; passage means providing a flow path between the discharge end of said impeller and the radially inner ends of said hollow struts and within which said auxiliary units are disposed for flow of cooling air over said units and radially outwardly through said hollow struts; and passage means providing communication between the radially outer ends of said hollow struts and said stator blade supporting structure for flow of cooling air from said struts over said stator structure.

5. A gas turbine power plant comprising a rotor; a hollow shaft drivably connected to said rotor; a stator cooperable with said rotor; a combustion chamber for supplying combustion gases for driving said rotor; an annular duct for receiving the exhaust gases from said rotor; said duct surrounding said shaft; a plurality of hollow struts for supporting said bearing and shaft, said struts extending throughsaid annular duct; an air impeller drivably connected to said shaft, said impeller supplying a portion of its air through said hollow struts for cooling said stator structure and supplying a portion of its air into said hollow shaft; a second air impeller drivably connected to said rotor, said second impeller being disposed on the side of said rotor opposite to said first-mentioned impeller and being varranged to receive air from said hollow shaft for supplying said air to the periphery of said rotor for cooling said rotor.

6. A gas turbine power plant comprising a rotor; a hollow shaft drivably connected to said rotor; a stator cooperable with said rotor; a combustion chamber for supplying combustion gases for driving said rotor; an annular duct for receiving the exhaust gases from said rotor, said duct surrounding said shaft; a plurality of hollow struts for supporting said bearing and shaft,

said struts extending throughY said annular duct; said impeller supplying aA portion of its air through said hollow struts for cooling said stator structure and supplying a portion of its air into said hollow shaft; a second hollow shaft drivably connected to said rotor adjacent to its periphery; a second air impeller drivably connected to said rotor, said second impeller being disposed within said second shaft on the side of said rotoropposite to said first-mentioned impeller and being arranged to receive air from said first-mentioned hollow shaft for supplying said air to the periphery of said rotor beyondthe connection. of said second shaft to said rotor for cooling said rotor periphery. Y WlllTON G. LUNDQUIST.

References Citedfin the le-ofthis'patentv Numberv UNrrii-:D` STATES PATENTS Name A p Date Lorenzen Aug. 30, 1927 Jodeiko Mar. 31, 1936 Auger May 10, 1938 Altorfer et al.l Jan. 28, 1947 lClegern Mar. 29,1949 McLeod Feb. 5, 1952 Buckland et a1. ,Apr. 1, 1952 FOREIGN PATENTS Country Date Great Britain May 1, 1939 Great Britain Apr. 1 9, 1950 

